Known types of painting installation, e.g. as disclosed in French patent No. 79 12 604, filed May 17, 1979 by Air Industrie, comprise an enclosure inside which a perforated floor is disposed, together with means for causing air to flow downwards inside the enclosure, means such as overflow chutes pouring onto trickle walls, serving to circulate water and mix it with the air that has passed through the enclosure, and a tank for collecting the water.
The air serves to entrain particles of paint that have not been deposited on the objects to be painted, and it is intimately mixed with water in a "washer". The water charged in this way is removed and also entrains any waste that may be produced inside the enclosure, either by operators passing therethrough, or else by periodic operations of cleaning the perforated floor and the various inside walls of the enclosure; the polluted water is generally purified and the residue is disposed of.